How To Grow Citrus Trees

Ever wanted to plant your very own citrus tree? Spring is upon us so now is the time to get your garden feeling fruity

Planting a lemon tree often marks the beginning of a bright and fruitful future in any Aussie garden. Its glossy green leaves provide shade in the warmer months as well as a good alternative to a privacy screen or hedge. The sweet perfume will waft through the garden when the delicate white flowers are in bloom and, three years from planting, your tree will produce a vibrant crop of lemons ensuring you’re never short of homemade lemonade in summer! However, planting citrus is not limited to just lemon trees; oranges, mandarins, limes, grapefruit and tangelos all are aesthetically beautiful and extremely beneficial to the overall ecology of your garden.

In Australia, our climate lends itself perfectly to growing citrus plants. Whether an ornamental dwarf fits your garden space, potted on your apartment balcony, or a more commercially available tree is what you are after, citrus plants will always thrive best with full sun exposure and shelter from damaging wind tunnels and areas highly affected by frost. Citrus plants are very economical in that the less sun exposure it gets the less fruit will be produced, which for the home gardener will provide a smaller crop that’s easier to manage.

How to prepare your garden to accommodate a citrus plant

Soil - all citrus plants thrive well in deep, well-drained loamy soil which is slightly acidic. Good drainage is essential for citrus as they are highly susceptible to root rot disease. Eliminating areas for planting that are in high flooding zones in your garden will ensure your citrus tree can grow to its full potential. If your garden consists mainly of harder soil simply add compost in a 2-metre radius of your plant when sowing. It is also advised to add gypsum to the soil which will add calcium to the soil without altering the pH levels as well as improve the structure of your soil to accommodate the new citrus being planted. If your garden has the opposite soil problem, a cow manure and compost mix are beneficial as it will assist in binding soils together and improve the nutritional levels for a healthier plant growth.

Planting - it is best to plant your citrus tree in spring. Spring is the ideal month for your plant to establish itself within the soil when it isn’t nutrient deficient from the cooler months or prone to disturbance in the hotter parts of the year. A general rule when planting a citrus tree is to dig a hole twice as wide as it is deep. Do not place any fertiliser in the hole, keep it bare as fertiliser can burn newly exposed, sensitive roots. Before planting, soak your tree roots thoroughly in water and do not remove until water bubbles come to the surface. By doing this you are preparing the plant for a sterile new environment. Now your plant is ready to be placed in the soil. Make sure the tree is level with the rest of the soil in the garden. If your garden consists of clay soils it is best to build a garden bed above the clay level. The reason for this is, if you dig into clay it will remain in the hole shape you created and pools will form under the surface when the plant is watered, resulting in too much water that will slowly kill your tree. Once your tree is firmly planted and filled in with soil, pat down the excess soil with your foot, this will prevent any extra run off into the rest of your garden. It is advised, once watered, to cover the soil around the tree with mulch to conserve moisture, however, be sure to leave a gap between the mulch and the trunk to prevent suffocation.

Planting in pots - If you are growing a citrus tree in a pot, choose a deep, non-porous container. Terracotta and clay pots will dry out too quickly if you are short on watering time. A deep pot will protect the roots from heat and, if it is light enough to lift, can be placed into a deep water container for a few hours to save time and water. Although citrus loves water, they do not like their roots to be constantly wet, so avoid sitting your pot in water 24/7. Potted plants are perfect if you are tight on space and by selecting dwarf varieties or citrus splitzers (two or more varieties of citrus grafted on to one root stock) you can still enjoy all the benefits of a citrus garden in a smaller space, balcony or patio. If you are feeling creative in your garden space, citrus are very versatile in that you can train your tree to grow flat against a wall or supported on a lattice frame, a practice known as espalier.

How to care for your citrus plant

Watering - during the summer months, citrus requires deep watering at least once per week around the drip line (the ground area at the outermost circumference of a tree canopy, where water drops form and drip on to the ground). This is also the most effective place to apply fertiliser so that the roots can easily take up the nutrients.

Fertilising - slow-release fertiliser specifically formulated for citrus trees is the most efficient fertiliser because it is a 3-monthly set-and-forget application. To help remember when to reapply, treat the tree at the beginning of each season or at the beginning of each quarter of the year. The fertiliser is not only good for the tree and the fruit, but also the soil. Nematodes feed on plant roots and starve crops of nourishment, thus reducing the amount of fruit produced. Telltale signs are tumour-like growths on plant roots. They thrive in tired, spent soil. A natural way to deter nematodes is to dig a hole under your tree, place prawn shells into the hole and then fill in the soil.

Pruning - pruning is only really necessary to remove deadwood and to cut away branches that are rubbing against each other. There is some advantage to training young trees to produce evenly spaced branches to allow light penetration into the centre of the tree. Just remember not to prune when the tree is budding or in flower, otherwise, you won’t receive any fruit that year. Should your citrus be badly burnt by a severe frost, do not prune it until you are sure the cold season has passed to avoid making the tree more vulnerable.

Citrus health - there are a few signs to look out for when caring for your citrus. If the leaves look shiny and firm then they are healthy and receiving enough water. On the other hand, if the leaves are crispy to the touch and limping off the branches, the tree needs more water. Similarly, if the leaves are yellow in colour you can be sure the plant is lacking iron. Iron can easily be placed back into the soil with a new feed of compost and an iron-booster which can be purchased in a fertiliser. You can tell a lot from the markings on citrus leaves, which can give insight into the health of a plant. If you find the leaves are yellow and have an inverted ‘V’ in the leaf base, then the tree is lacking in magnesium. To regain healthy magnesium levels in your plant use a tablespoon of Epsom salts dissolved in 9 litres of water and pour around the dripline of the tree as well as over the leaves.

Disease and pest control - citrus trees are prone to a few pests and diseases, so be vigilant. Look out for citrus leafminer, the larvae of a small moth which causes distortion in new growth. It can only be sprayed with an oil spray (white oil and pest oil) during the growing season, from late spring through to autumn. The spray makes the leaf surface slippery, undesirable and difficult for pests to inhabit the tree. The spray is a natural pest control method and also deters aphids (which attack new growth), bronze orange bug (also known as stink bugs) and scale insects. When using pest oils to control scale insects and bronze orange bugs, do not spray on the leaves in the hottest part of the day, as the oil can burn the leaves. A good tip to prevent the spread of fruit fly is to place dropped and stung fruit into your garbage bin, not your compost bin. Otherwise, the pests will continue to breed.